Trigonometric resolving apparatus



April 5, 1960 J. K. sToRY 2,931,573

" TRIGONOMETRIC REsoLvING APPARATUS Filed Sept. l5, 1955 IN VEN TOR.

United States Patent() TRIGONOMETRIC RESGLVING APPARATUS James K. Story,Long Beach, Calif., assignor to V. E. Kuster, Long Beach, Calif.

Application September 15, 1955, Serial No. 534,561 s claims. (crass-189) This invention relates to improved trigonometric resolvingapparatus for developing a representation of a point in polarcoordinates. The present application constitutes a continuation-in-partof my copending application Serial No. 465,281, tiled October 28, 1954,and now Patent No. 2,843,941, on Well Surveying Apparatus.

The general object of the invention is to provide apparatus which iscapable of transforming rectangular co ordinates into polar coordinates,or for solving problems which are analogous to such transformation fromrectangular to polar coordinates. For instance, in the well surveyingequipment of the above entitled parent application, the present deviceis utilized for solving the analogous problem of combining twocomponents of a well bore inclination into a single representation ofthat inclination, defined in terms of the angle of inclination and itsdirection.

In accordance with the invention, I employ apparatus including anelement which is movable in two essentially perpendicular directions toa position having predetermined coordinates in those two directions. Fortransforming that position into polar coordinates, l provide a rstelectrical lunit which isactuable in accordance with the distancebetween the element and a predetermined center, and a second electricalunit which is actuable in accordance with the rotary positioning of theelement about the center. The element' may be moved in'the two desireddirections by two essentially perpendicular. screw and nut assemblies.

Both of theelectrical units may be potentiometersv swinging about thecenter of the-device, the first -potentiometer preferablyl being of thelinear motion linear winding type, and the second. preferably beingofthe ice ends to form a rigid rectangular horizontally extending frame,and four vertically extending corner posts or legs 14. At a locationspaced above the members 13, legs 11 support an upper horizontal topplate 15.

Two parallel laterally spaced elongated rotary lead screws 16 aremounted to framework 11 for rotation about their individual parallelhorizontally extending axes, the mounting typically being effected bysuitable bearings 17 attached to the framework and journaling coactingunthreaded portions of screws 16. Bearings 17 are of course designed toprevent axial movement of screws 16, while allowing the desired rotarymovement of these screws.

One of the screws 16 is mechanically driven by a motor l-M, as through aconnection including a reduction gear unit 18 and a pair of bevel gears19. The second of the screws 16 is rotatably driven in unison with thefirst, typically by providing a pair of gears 20 on the two screws, withan intermediate power transmitting gear 21, mounted by one or morebearings 23, meshing with and transmitting power between the two gears20.

A third screw element 22 extends perpendicularly to and between screws16, vand is rotatably journaled within a pair of bearing blocks 123carried by the two screws. Each of these bearing blocks contains athreaded bore through which the corresponding screw 16 extends, so thatrotation of screws 16'in unison acts to displace blocks 123 and-theirrotatably carried screw 22 axially relative to screws 16. The bearingengagement between blocks 123 and screw 22 is such as to allowrrot'arymovement of screw 22 in the blocks, while preventing axial movement ofscrew 22v relative to the blocks.

The third screw 22 is driven by a motor 2-M, typically through a speedreduction gear unit 24 and a liexible drive connection represented at25. Motors l-M and 2-M may be mounted in any suitable manner to theframework 11, as by mounting the motors and their reduction gear unitsto a supporting platform 26 stationarily attached to and projectinglaterally from one of the members 13. Screw 22 threadedly carries a nutelement or block 27, which is actuated axially along screw 2,2 by and inaccordance with rotation of that screw.

' VThe block 27 is suitably retained against rotary movement rotarymotion linear winding type. The rotary potentiometer may have the usualrelatively rotatable contact and resistor parts, one of which, desirablythe contact, is 'rotatable about the center in accordance with movementof the element whose coordinates are being determined. The other part ofthe potentiometer may also be rotatable if desired, to introduce acorrection'factor into the readingof the potentiometer. This correctionfactor, and the two input rectangular coordinates, may be introducedinto the device by three electric motors; land the output polarcoordinates may be readout by suitable indicators.

The above and other features and objects of the present invention willbe better understood from the following V' detailed description of thetypical embodiment illustrated in the accompanying drawing in which:

Fig. l is a plan view of a resolving device constructed in accordancewith the invention;vk

Fig. 2 is a vertical section takenl or1` line 242 of Fig. i l; and

Fig. 3k is an enlarged fragmentary vertical section taken on. line 3--3of Fig. l.

The resolving device 10 illustrated in the drawing has a stationaryframe structure 11 which may rest onl a suitable supporting surface 12.This frame structure 1-1 includes four rigidmembers 13 interconnected attheir about the axis of screw 22, preferably by provision of a rod 28rigidly carried by and extending between blocks 123. This rod 28 extendsparallel to screw 22, and passes through a guide opening 29 in the blockor nut 27,k to slideably lguide that block for only axial move? mentrelative to screw 22. Y i

As will be apparent, the described screws 16 and 22 driven by motors l-Mand 2-M, are capable of displacing block 27 to an infinite number ofdiiierent positions within its plane of movement and about a centralreference point or axis 30. Motors 1-M and Z-M may be Venergized byelectrical input signals to actuate their respective screws 16 and 22 ina manner displacing nut 27 to avposition having rectangular coordinatesdetermined by the input signals. That is, motor 1-M is energized by asuitable control circuit for a period sufficient to move blocks 123 andscrew 22 (by rotation of screws 16) a predetermined distance from `aposition of alinement with center point 30. Similarly, motor Z-M may beenergized to rotate screw 22 and thereby move nut 27 along screw 22 to aposition representing a second rectangular coordinate at a desired pointin the plane of movement of block 27. After block 27 has been thusactuated by screws 16 and 22 to a particular position, the polarcoordinates of that position with respect to center point or axis 30 aredeveloped in electrical form by two potentiometers 31 and 32. The tirstof these potentiometers 31 is of the linear motion and linear windingtype, and includes an elongated tubular body 33 which conassura tricallyinsulated carrier element 36. Contact 35 is'car-l ried by an elongatedarm 37, which is guided for' onlyV longitudinal sliding movementrelative to body 33 and re-l sistor winding 34, the guiding actiondesirably being attained by means of one or more elongated guide rods 38within and carried by body 33 and extending through guide openings 39 inan electrically insulative member 40 projecting from element 37. Also,body 33 may have a bearing portion at 41 which assists in guidingelement 37 and the carried contact 35 for only the desired longitudinalmovement. Contact 35 is of course suitably insulated from resistorwinding 34 except at the point of contact between these parts. Theopposite end of element 37 is pivotally attached at 42l to block 27.

Potentiometer 31 is mounted for swinging movement about axis 30 (whichextends perpendicular to the plane within which block 27 moves). Thismounting` of potentiometer 31 for swinging movement may be effected bymeans of a shaft 43 which is Ajournaled by bearings 44 for rotationabout axis 3G, and which is desirably retained against axial movementwithin bearings 44. Bearings 44 may be attached at first locations tothe previously mentioned transverse plate 15, and adjacent a centralopening 45 in this plate through which shaft 43 extends. At its lowerend, shaft 43 has a portion 46 which is offset laterally from axis 30,and is rigidly attached to potentiometer body 33, as by a screw 47. Thevoffset relation of portion 46 of shaft 43 is sufficient to allowmovement of block 27 to the exactcenter of its plane of movement, thatis to a position at which the pivotal connection 42 is Vexactly alinedwith the center axis 30. The mountnig of potentiometer 31 is Ysuch thatelement 37 and contact 35 move in planes which are parallel to or arethe same as the plane of movement of block 27.

Potentiometer 32 serves to respond to the rotary positioning of block 27about axis 30, and is a 360 rotary motion linear winding potentiometer.This potentiometer includes a shaft 48 which is rigidly attachedrto andin alinement with shaft 43 by a set screw 49, to thus rotate about axis30 with shaft 43. If desired, an upper bearing 49 carried by a bracket50 attached to plate 15 may be provided for journaling and accuratelylocating the upper end of shaft 48. Potentiometer 32 includes also anouter circular housing 51, which may itself contain a pair of bearing orbushing elements 52 journaling shaft 48 for rotation within housing 51.Housing 51 contains a circular 360 linearly woundvlresistorwire orelement'- 53, which is electrically engaged by a relatively rotatablecontact 54 rigidly attached to and rotatable with shaft 48. The outersurface of body 51 takes the form of a potentiometer 31, in whichposition there is no difference in potential between these two movablecontacts, and as a result no current flows to the amplifier and motor4-M. If contact 35 is moved from such a balanced position, a differenceof potential is developed between the two movable contacts ofpotentiometers 31 and 59, causing current to fiow to the amplifier andmotor in a direction for l driving the motor and thereby the movablecontact of potentiometer 59 in correspondence with the movement ofcontact 35 along its resistor. This movement continues until there isagain no difference in potential between the two movable contacts. Thereadout circuit between potentiometer 32 and motor S-M is the same asters which are driven by motors 4-M and S-M to positoothed gear, whichmeshes with and is driven by a Worm The positions of the twopotentiometers 31 and` 32 Aare l indicated to an operator by means of apair of indicators 56 and 57 driven by two motors 4-M and S-Mrespectively. These motors may be Adriven by null balancesystems of thetype represented generally in Fig. l. For instance, in the case ofpotentiometer 31, the resistance element 34 of the potentiometer isconnected to a battery 58 in parallel with the resistance element of asecond potentiometer 59. The movable contacts of these twopotentiometers are connected to an amplifier 60, whose output isutilized to drive motor 4-M. Motor 4-M in turn is mechanically connectedto the movable contact of potentiometer 59 to actuate that potentiometerin accordance with rotation in either directionof motor 4-M. Motor 4-Malways returns the movable contact of ypocoordinates of that point.

tionsV representing directly the positions of the two motors andthereforethe settings of potentiometers 31 and 32. In describing the useof the illustrated apparatus, assume that we are given the rectangularcoordinates of a point in a plane, and it is desired to obtain the polarThe first step is to energize motor 1-M in accordance with one of therectangular coordinates (parallel to the axes of screws 16), and toenergize motor 2-M in accordance with the second and relativelyperpendicular coordinate (parallel to screw 23). That is, motor l-M maybe fed an electrical signal, which is suitably controlled, to drivescrews 16 until the center of pivotal connection 42 is offset thedesired distance or coordinate 61 from center axis 30 in a directionvparallel to screws 16. Similarly, motor 2-M is energized for a periodsufficient to move block 27 along screw 22 to a point at which thecoordinate 62 of pivotal connection 42 with respect to center 30 is thedesired value. vSuch energization of motors 1-M and 2-M accuratelypositions pivotal connection 42 in accordance with the known rectangularcoordinates relative to the center 30. Assuming that motor 3M andhousing 51 of potentiometer 32 are set in a predetermined zero position,indicators 56 and 57 will indicate the polar coordinates of pivotalconnection 42 after the defined energization of motors l-M and Z-M. Thatis, the setting of potentiometer 31 will correspond to the vdistancebetween axis 30 and the center of pivotal connection 42, while thesetting of potentiometer 32 will correspond with the rotary position ofpivotal connection 42 about axis 30. These settings of thepotentiometers 31 and 32 are transmitted to indicators 56 and 57 bymeans of the previously described readout potentiometers 59 and 59a,motors 4-M and S-M, and associated parts. If it is desired in theparticular problem being handled to introduce a correction into ,theangleindicated by-indicator 57 (which indicator preferably readsdirectly in degrees), motor 3-M may be energized torotatively displacehousing 51 and resistor element 53 of potentiometer 32 relative topointer 54 and about axis 30, so that the readingv at indicator 57 isappropriately corrected. As will be apparent, the illustrated apparatusmay of course be utilized in numerous different situations whereproblems analogous to the one discussed above are to be solved.

I claim:

l. A resolver comprising an elementrmovable in two different mutuallyperpendicular directions within essentially a predetermined plane andrelative to a center axis extending essentiallyV` perpendicular to saidplane, first means for actuating said element in one of said directionsrelative to said axis to represent a first coordinate of a point, secondmeans for actuating said element in the second of said directionsrelative to said axis to represent a second coordinate of said point, alinear motion Velectrical control unit mounted to swing about said axisand connected to said element in a relation to be actuated tentiometer`59 vto. .a position corresponding to that of l75 thereby in accordancewith the distance of said element from said axis'and to thereby controlan output signal in accordance with said distance, and a rotary motionelectrical control unit having an actuating part mounted for rotarymovement about said axis and actuable about said axis in accordance withthe Vrotary positioning of said element thereabout to thereby controlanoutput signal in accordance with said rotary positioning, said rotarymotion unit including two sections which are relatively rotatable aboutsaid axis one having a resistor element and the other having a contactmovably engaging said resistor element, means for rotating a iirst ofsaid sections about said axis in correspondence with the rotary movementof said element about the axis, and means for rotatively moving thesecond of said sections about said axis independently of the rotarymovement of said first section and to positions of different orientationwith respect to said perpendicular directions.

2. A resolver as recited in claim 1, in which said rst section carriessaid contact and said second section carries said resistor element, saidlinear motion unit being a linear potentiometer connected to said tirstsection for swinging movement therewith about said axis and adjustableradially of said axis.

3. A resolver as recited in claim l, in which said linear motion unit isconnected to one of said sections for swinging movement therewith aboutsaid axis.

4. A resolver as recited in claim 1, in which said element is movable bysaid actuating means to a position at which said point representedthereby coincides exactly with said axis, said linear motion unitincluding a body portion mounted to swing about said axis with one ofsaid sections of the rotary motion unit but offset from said axis toavoid interference with movement of the element to said axis, saidlinear motion unit including also a second portion which is actuated bysaid element relative to said body portion and radially of said axis.

5. A resolver as recited in claim l, in which said last mentioned meanscomprises an electric motor for rotatively adjusting said second sectionabout said axis.

References Cited in the file of this patent UNITED STATES PATENTS1,985,265 Smith Dec. 25, 1934 2,538,226 Anderson et al. Jan. 16, 1951FOREIGN PATENTS 648,384 France Aug. 13, 1928

